Polytonality is a related term of polytonal.

In music|lang=en terms the difference between polytonality and polytonal

is that polytonality is (music) the use of multiple keys in the same composition, especially by multiple instruments at the same time while polytonal is (music) that uses two or more tonalities simultaneously.

As a noun polytonality

is (music) the use of multiple keys in the same composition, especially by multiple instruments at the same time.

As an adjective polytonal is

(music) that uses two or more tonalities simultaneously.